Self-sealing door



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Feb. 5, 1957 F, DOLL 2,780,590

SELF-SEALING DOOR Filed Dec. e, 1952 2 sheets-'sheet 1 FRA NZ DOLL faQ/wm I 'bsarroR/Jgr Feb. 5, 1957 F. DOLL SELF-SEALING DOOR Filed Deo. 6l1952 7 22- 9 zo. l

7 l I 7 2q la INvfNrO/e FRANZ DOLL,

QTTOPA/g y United States Patent O SELF-SEALING DOOR Franz Doll, Essen,Germany, assignor, by mesne assignments, to Koppers Company, Inc.,Pittsburgh, Pa., a corporation of Delaware Application December 6, 1952,Serial No. 324,571

8 Claims. (Cl. 202--248) The invention relates to self-sealing doors forhorizontal coke ovens or the like, such doors being of the kind havinglatch bars adapted to engage latch hooks projecting from the door frame,and having a sealing frame mounted on the door in a circumferentialrecess.

Coke oven doors are known in which a web-like or flat sealing frame ismounted, with an asbestos packing, in a circumferential recess in thedoor body in order to prevent escape of gas. However, sealing framesmounted in this manner can only with diiiculty be kept leak-proofbecause of the constant movement to which such frames are subjected bythe positioning of the door, and in addition, the sealing frame is mademore or less rigid and only has a -slight degree of resil-ience toada-pt itself to the irregularities of the door frame which occur inoperation.

The present invention provides a door having a sealing frame whichprovides a high degree of resilience and also satisfactory sealingconditions at the point of connection of the sealing frame with the doorbody and while pressed Iagainst the door frame of a coke oven door inclosed position of the door. Moreover, a door constructed in ac cordancewith the present invention also has the advantage, that it does notrequire mountings on the door body for the pressure screws for thesealing frame, so that there isample space for introducing a widelevelling bar into an oven closed by such door.

A door constructed in accordance with the present invention ischaracterised in that the sealing member in vthe form of a frame isZ-shaped in cross-section and bears with the free edge of one of itslimbs against the sealing surface of the door frame of a coke oven andis mounted imperforately with its other limb gastightly sealed in thesaid circumferential recess in the door body.

Such a construction and imperforate mounting of the sealing frame on thedoor provides greater resilience for the limb which. bears against thesealing surface on the coke oven, whereby the imperforately clamped limbsealed in the recess in the door body can be pressed so rmly against thelatter by stud screws laterally through an outer side wall of the recessagainst an inner wall thereof that in'practice scarcely anydisplacements of the said clamped limb take place and thus the sealingat the clamping point is only slightly stressed. i

According to a further feature of the invention, the resilience of thesealing frame may be increased by furnishing the web between the twolimbs of the Z-shaped scaling frame with longitudinal recesses.

Furthermore, according to the invention, that limb of the Z-shapedsealing frame which is sealed in the said recess in the door body may beclamped, by pressure `screws arranged laterally in the outer wall of therecess, against sealing means arranged in said recess to form a caulkedjoint between said limb and the door body. This caulked joint preferablybears against a comparatively narrow region of the bearing surface ofthe limb of the sealing frame, so that the major bearing surface part ofsaidlimb only requires a comparatively thin packing.

2,780,590 Patented Feb. 5, 1957 At the four rectangular corners of thedoor body, however, the caulked joint is preferably enlarged to extendover the entire bearing surface of the limb of the sealing frame, sothat the latter can be reliably fitted even when the cast door body isnot accurately machined at the According to a further feature of theinvention, the

'As a result of such resilient mounting of the pressurel means of thesealing frame, the resilience of the sealing frame is such that thelatter can easily accommodate all irregularities of the door frame andthe door itself which may occur in operation.

In order to be able to determine at what points compression of thesprings may have to be adjusted as a result of deformation of the doorframe or door body, the said pistons may each be provided with a stemwhich so passes through a bore in its associated adjustable pressurescrew that the end of the stem is visibly flush with the visible end ofthe pressure screw when the spring associated therewith is under itsproper compression; thus it is possible at any time to carry out asimple adjustment" of the spring pressure to compensate for door frameor door body deformation by adjusting pressure screws until the` endsthereof are visibly flush with the ends of the said piston stems.

One embodiment of the invention is shown by way of example in theaccompanying drawing, wherein:

Figure 1 is a horizontal section of a door constructed in accordancewith the invention, the door being in the yclosed position in a doorframe of an oven chamber; and

Figure 2 is an enlarged horizontal section of the means by which thesealing frame is imperforately secured in the door body and pressedagainst the door frame'.

As shown in the drawings, a refractory plug 1, carried by the door body9 which is of cast iron, projects into the oven chamber 2 when the dooris in its closed position.

The oven comprises refractory walls 3, in which are disposed heatingflues 4, between the indvidaul oven chambers, the front ends of thewalls 3 being covered by a refractory insulating layer 5. The refractoryinsulating layer 5 of the oven battery is lined with an ironreinforcement 6 against which bears the door frame 7 surrounding eachopening of the oven chamber, said frame 7 being connected by suitablemeans such as screws or the like with the iron reinforcement 6.

`The inner refractory plug 1 is embraced by a frame 8 having a ange bywhich it is connected with the castiron door body 9. The rugged outermetallic cast-iron door body 9 is formed with a peripheral web 10 whichhas a fork-like section at its junction with the body 9'vso that aninwardly open circumferential recess 11, of U-shape in cross-section,is. formed as clearly shown in the drawings. A rectangularcircumferential sealing frame 12 having a Z-shape cross-section ismounted by means of one of its limbs 13 in the U-shaped recess 11;

the other limb 14 of the sealing frame 12 bears againstl mounted to forma caulked joint 17 on the inner wall forming the U-shaped recess. Thiscaulked joint 17 is disposed on the oven side of the axes of thepressure screws 16, so that o nly a comparatively thin asbestos plate18er the like is necessary to seal the remainder of the limb 13 in therecess 11.

Such an asbestos plate 18 is suicient on the vertical longitudinal andhorizontal transverse surfaces of the re,-

in Figure 2) in suchVv manner that the entire corner por#A tions of thesurface of the limb 13 bears against the caulked joint. The weblconnectingthe vtwo limbs 13 and 14 ofthe sealing frame 12 is formedwith longitudinalrecesses 2 0 which give a satisfactory degree ofresilience tothesealing frame.

In the closed position of the door, pistons 21 act on tl1 e limb 1 4 ofthe sealing frame,. said' pistons being mounted for axialldisplacen'ient in bores 22 of lugs 23. The lugs 23 arepreferablyintegrallycastwith the'outer wallof therecess 11`. Each b0re 22 isformed withan internal thread into which is screwed a .pressure screw24,.,the screw 24 having a .bore.25 through which extends a stern 26ofth e piston 21. A4 set of plate springs 27 is arrangedbetween the piston21 arid the inner endof the screw, 24, these springs being of suchstrength tha'tthe necessary bearing pressure of the sealing frame 12upon thesurface of the door frame 7 .is attained when the.

screw 24 is screwed so far into the thread of the borev 22.v

that, when the door is closed, the end of the stern 26 of the .pistonl21is flush with the outer end of the screw 24..

.When local irregularities of the sealing surface 15 of tlie door frame7 occur, the stem 26 shows beyond the hea'd of the screw 24. By.unscrewing the screw 24 to such an extent that the end of the stem 26 isagain ush` witnthe' outer end of the head of screw 24, the normalclosing pressure of the springs 27 is restored.

The door is locked in its closed position by means of latch bar s 28,rotatably mounted on latch bolts 29, which latch bars are adapted toengage with latch hooks -connected tov the door frame 7. The latch bolts29 are mounted in bearings forming a part of housing 31 connected withthe door body 9. Preferably the closing pressure of the door is producedby springs which are shown mounted inthe housing 31, such' springsurging the latch bars 28 away from the door body 9. Upon' fitting the'door, these closing springs must be compressed somewhat by means of thelatch bolts 29, this compression being relieved after swinging the bars28 into engagement with the hools 30.v The v compression of the closingsprings is obtained either by rotating the latch bolts 29 or by axialpressure for instance, pneumatic pressure', zip' idt the latch bolts 29and the collar for the latch bai-sI by the door-handling machine.

The invention as hereinabove set forth is embodied Ain particular formsand manners, but may be variously embodied within the scope of theclaims hereinafter made.

1. A self-sealing coke ovendoo'r comprising a door b dy; a rectangularcircumferential sealing frame recess on said door body in surroundingrelation therewith com pi'isiig in Across-se'cition oppositely disposedinner and ofitr vs'ide" walls and an open entrance passage ybetween theside walls facing toward a coke oven doorway in closed position of thedoor; a rectangular sealing framev of z -slape in cross-section, havinglongitudinalrecesses in the web between the two limbs of the Z-shape of'the frame, arranged in surrounding relation with lthe door body withone limb extending from the web inwardly of the door and terminating ina free lsealing edge in position for sealing engagement against asealing surface therefor on vva door frame for the door in its closedposithe Z-shape extending from the web of the frame out# wardly of thedoor and freely slidable into and out of the circumferential recessalongside the inner wall through its open entrance passage from theinner side of the door; pressure stud screws accessible for manipulationfrom the exterior of the frame recess and extending laterally throughthe outer side wall of the frame recess and into the recess spacebetween the inner and outer wallsv thereof in pressure abuttingimperforate relation with the limb of the frame alongside the inner wallin the frame recess, for imperforat'ely clamping saidy limb gas tightagainst said inner walI; said inner side-wall being spaced a distancecloser to the axis of the door body in the region between the' studscrewsv and the web of the Z-shaped frame throughout the longitudinaland horizontal parts of the recess, than in the region between the studscrews and the outer fr ee edgeof the limb in the recess, forcaulkingthe space between'said inner wallof the recess and the limb ofthe Z-shape framel therein,` from the inner side of the door, withpacking. that is thicker throughout the longitudinal and horizontalpartsv of thelimb in the recess, in the ,region between the stud screws'and the web of the Z-shape frame, than in the region alongside the innerwall of the recessbetween the stud screws and the outer free edge of thelimb" in the recess; and adjustable pressure means mounted alongside.and' accessible from the exterior of, the outer side wall of thecircumferential rectangularfrarne recess, for exertin g sealing pressureon the inwardly extending limb to its terminal free sealing edge againsta sealing surface on a door frame in closed position of the door, saidadjustable pressure means each comprising a piston acting on the limb,an adjustable screw, a pressure transmitting spring interposed betweenthe piston andthe adjustable screw,y a bore in the adjustable screw, anda stern on the piston extending through the bore and terminating in anoutwardly visible flush relation with an outwardly visible surface 4ofthe adjustable screw, when the door is closed with the spring at normalsealing pressure.

,2. A cokeoven door as claimed in claim l, rand in which the portions ofthe inner side wall of said recess atthe cornersof the rectangularcircumferential sealing frame recess are at a greater distance closer tothe axis of the door body alongside the portions of the limb from theweb to the free edge of the limb than the distance of the portions ofthe inner wall of the recess alongside the portions of the limb betweenthe stud screws and theouter free edge of the limb in the region betweenthe corners of the recess frame.

3. A self-sealing coke oven door comprising: a door body; a rectangularcircumferential sealing framerecess o u said door body in surroundingrelation therewith comprising in cross-section oppositely disposed innerand outerside walls andan open entrance passage between theside wallsfacing toward a coke oven doorway in closed position of the door; arectangular sealing frame of Z-shape in cross-section, havinglongitudinal recesses ijn the web lbetween the two limbs of the Z-shapeof the frame, arranged in surroundingrelation with the door body withone limb extending from the web inwardly ofthe door and terminating in afree sealing edge in position for sealing engagement against a sealingsurface therefor on a door frame for the door in its closed position ona coking chamber, and with the other limb of the Z-'shape extending fromthe web of the frame outwardly of the door and freely slidable into andout of the circumferential recess alongside the inner wall through itsopen entrance passage from the inner side of the door; pressure studscr'ews accessible for manipulation from the exterior of the framerecess and extending laterally through the outer side wall of the framerecess and into the 'recess space between the inner and outer wallsthereof inlpressureA abuttingv imperforate relation with the limb 'ofthe frame alongside the inne'r irtall in the `frame recess, forimperforately clamping said limb gas tight against said inner wall; saidinner side Wall being spaced a distance. closer to the axis of the doorbody in the region between the stud screws and the web of the Z-shapedframe throughout the longitudinal and horizontal parts of the recess,than in the region between the stud screws and the outer free edge ofthe limb in the recess, for caulking the space between said inner wallof the recess and the limb of the Z-shape frame therein, from the innerside of the door, with packing that is thicker throughout thelongitudinal and horizontal parts of the limb in the recess, in theregion between lthe stud screws and the web of the Z-shape frame, thanin the region alongside the inner wall of the recess between the studscrews and the outer free edge of the limb in the recess; and adjustablepressure means mounted alongside, and accessible from the exterior of,the outer side wallof the circumferential rectangular frame recess, forexerting sealing pressure on the inwardly extending limb to its terminalfree sealing edge against a sealing surface on a door frame in closedposition of the door.

4. A self-sealing coke oven door comprising; a door body; acircumferential sealing frame recess on said door body in surroundingrelation therewith comprising in cross-section oppositely disposed innerand outer side walls and an open entrance passage betweenvthe side wallsfacing toward a coke oven doorway in closed position of the door; asealing frame of Z-shape in crosssection, having longitudinal recessesin the web between the two limbs of the Z-shape of the frame,.arrangedin surrounding relation with the door body with one limb extending fromthe web inwardly of the' door and terminating in a free sealing edge inposition for sealing engagement against a sealing surface therefor on adoor frame for the door in its closed position on a coking chamber, andwith the other limb of the Z-shape extending from the web of the frameoutwardly of the door and freely slidable into and out of thecircumferential recess alongside the inner wall through its openentrance passage from the inner side of the door; pressure stud screwsaccessible for manipulation from the exterior of the frame recess andextending laterally through the outer side wall of the frame recess andinto the recess space between the inner and outer Walls thereof inpressure abutting imperforate relation with the limb of the framealongside the inner wall in the frame recess,

said inner wall; said inner side wall being spaced a distance closer tothe axis of the door body in the region between the stud screws and theweb of the Z-shaped i frame throughout the longitudinal and horizontalparts of the recess, than in the region between the stud screws and theouter free edge of the limb in the recess, for caulking the spacebetween said inner wall of the recess and the limb of the Z-shape frametherein, from the inner side of the door, with packing that is thickerthroughout the longitudinal and horizontal parts of the limb in therecess, in the region between the stud screws and the web of the Z-shapeframe, than in the region alongside the inner wall of the recess betweenthe stud screws and the outer free edge of the limb in the recess; andadjustable pressure means mounted alongside, and accessible from theexterior of, the outer side wall of the circumferential frame recess,for exerting sealing pressure on the inwardly extending limb to itsterminal free sealing edge against a sealing surface on a door frame inclosed position of the door.

5. A self-sealing coke oven door comprising: a door body; acircumferential sealing frame recess on said door body in surroundingrelation therewith comprising in cross-section oppositely disposed innerand outer side walls and an open entrance passage between the side wallsfacing toward a coke oven doorway in closed position of the door: aAsealing frame of Z-shape in crosssection, arranged in surroundingrelation with the door bod'y with one limb extending from the webinwardly of 'tlie door and terminating in a free sealing edge inposition for sealing engagement against a sealing surface therefor on adoor frame for the door in its closed position on a coking chamber, andwith the other limb of the Z-shape extending from the web of the frameoutwardly of the door and freely slidable into and out of thecircumferential recess alongside the inner 'wall through its openentrance passage from the inner side of the door; pressure stud screwsaccessible for manipulation from the exterior of the frame recess andextending laterally through the outer side wall of the frame recess andinto the recess space between the inner and outer walls thereof inpressure abutting imperforate relation with the limb of the framealongside the inner wall in the frame recess, for imperforately clampingsaid limb gas tight against saidinner wall; said inner side wall beingspaced a distance closer to theaxis of the door body in the regionbetween the stud screws and the web of the Z-shaped frame throughout thelongitudinal and horizontal parts of the recess, than in the regionbetween the stud screws andthe outer free edge of the limb in therecess, for caulking the space between said inner wall of the recess andthe limb of the Z-shape frame therein, from the inner side of the door,with packingthat is thicker throughout the longitudinal and horizontalparts ofthe limb in the recess, in the region between the stud screwsand the web of the Z-shape frame, than in the region alongside the innerwall of the recess between the stud screws and the outer free edge ofthe limb in the recess; and adjustable pressure means mounted alongside,and accessible from the exterior of, the outer side wall of thecircumferential frame recess, for exerting sealing pressure on theinwardly extending limb to its terminal free sealing edge against asealing surface on a door frame in closed position of the door, saidadjustable pressure means each comprising a piston acting on the limb,an adjustable screw, a pressure transmitting spring interposed betweenthe piston and the adjustable screw, a bore in the adjustable screw, anda stem on the piston extending through the bore and terminating in anoutwardly visible ilush relation with an outwardly visible surface ofthe adjustable screw, then the door is closed with the spring at normalsealing pressure.

6. A self-sealing coke oven door comprising: a door body; acircumferential sealing frame recess on said door body in surroundingrelation therewith comprising in cross-section oppositely disposed innerand outer side walls and an open entrance passage between the side wallsfacing toward a coke oven doorway in closed position of the door; asealing frame of Z-shape in crosssection, arranged in surroundingrelation with the door body with one limb extending from the webinwardly of the door and terminating in a free sealing edge in positionfor sealing engagement against a sealing surface therefor on a doorframe for the door in its closed position on a coking chamber, and withthe other limb of the Z-shape extending from the web of the frameoutwardly of the door and freely slidable into and out of thecircumferential recess alongside its inner wall through its openentrance passage from the inner side of the door; pressure stud screwsaccessible for manipulation from the exterior of the frame recess andextending laterally through the outer side wall of the frame recess andinto the recess space between the inner and outer walls thereof inpressure abutting imperforate relation with the limb of the framealongside the inner wall in the frame recess, for imperforately clampingsaid limb gas tight against said inner wall; said inner side wall beingspaced a distance closer to the axis of the door body in the regionbetween the stud screws and the web of the Z-shaped frame throughout thelongitudinal and hori` zontal parts vof-the recess, ,than in, the regionbetween the stud screw s. and theoutenfree edge f-the limb ill-therecess, for caulking the space between said inner wall of they recessand the limb of the -Zfshape frame therein, from the inner side of thedoor, with packing that is thicker throughout the longitudinal andhorizontal parts of the limb in the recess, in theregion between thestud screws and the web of the Z-shape frame, than in the regionalongside the inner wall of thevrecess, between the stud screws and theouter free edge of the limb in the recessgvand adjustable pressure meansmounted alongside, and accessible from the exterior of, the outer sidewall of thecircumferential frame recess, for exerting sealing `pressureon the inwardly extending limb to, its terminal free sealing edgeagainst a sealing surfaceon a doonframein closed position of the door.

7, A selfsealing coke oven door comprising, in cornbination:` aninnerplug member;v atl'exible sealing member extending around theperiphery of the door; a rugged outer metallic member arranged outwardlyfrom said sealingmember; a plurality of resilient adjusting meansdisposed around the peripheryl of said outer metallic member andarranged for exerting resilient pressure on said sealing member, eachsaid resilient adjusting means comprising a piston acting on the sealingmember, an adjustable screw, a pressure transmitting springinterposedbetween the piston and the adjustable screw, a bore intheadjustable screw, and a stem on the piston extending through the boreand terminating in an outwardly visible flush relation with an outervisible surface of .the adjustable screw, when the spring is at normalsealing pressure in the closed position of the door.

8. A self-sealing coke oven door comprising, in cornbination: an innerplug member; a flexible sealing memberarranged around the periphery ofthe door; a rugged outer metallic member arranged` outwardly fromsaidsealing member; a peripheral recess for seating said; sealing -member insurrounding relation with said rugged outer member, saidrecess'comprising in cross-section oppositely-disposed inner and outerside walls and' an open* entrance'passage between the side Awalls andfacing toward acoke oven door-wayin `closed position of thedoor;said'sealingmember being freely slidableinto and out of theperipheral; recess alongside its innerside wall through its'openentrance passage from the inner side of the door; pressure `stud screwsextending laterally through the outer side wall of ythe recess for thesealing member into the recess space between'the inner and outerwal'lsthereof in pressure abutting imperforate relation 'withthe'sealing vmember alongside the inner wall ci: the recess, forlimperforately clamping said sealing member gas tight against said innerwall; and a` plurality of adjusting-means disposed around the-peripheryof said rugged louter metallic member and arranged -for exertingsealingpressure onV said sealing member against a sealing'surfacetherefor on a coke -oven chamber in the closed position of'the door.

References Cited in the tile of this patent UNITED' STATES PATENTS1,093,522 l Bareuter Apr. 14, 1914 2,175,217 v .Salk vist Oct, 10, 1939v.2,244,671 -Berg etal. June 10, 1941 `2,478,215 Van'Ackeren Aug. 9,1949 'FOREIGN PATENTS .675,478 Germany May 9, 1939 853,827 Fra-nce Dec.16, 1939

1. A SELF-SEALING COKE OVEN DOOR COMPRISING A DOOR BODY; A RECTANGULARCIRCUMFERENTIAL SEALING FRAME RECESS ON SAID DOOR BODY IN SURROUNDINGRETLATION THEREWITH COMPRISING IN CROSS-SECTION OPPOSITELY DISPOSEDINNER AND OUTER SIDE WALLS AND AN OPEN ENTRANCE PASSAGE BETWEEN THE SIDEWALLS FACING FORWARD A COKE OVEN DOORWAY IN CLOSED POSITION OF THE DOOR;A RECTANGULAR SEALING FRAME OF Z-SHAPE IN CROSS-SECTION, HAVINGLONGITUDINAL RECESSES IN THE WEB BETWEEN THE TWO LIMBS OF THE Z-SHAPEDOF THE FRAME, ARRANGED IN SURROUNDING RELATION WITH THE DOOR BODY WITHONE LIMB EXTENDING FROM THE WEB INWARDLY OF THE DOOR AND TERMINATING INA FREE SEALING EDGE POSITION FOR SEALING ENGAGEMENT AGAINST A SEALINGSURFACE THEREFOR ON A DOOR FRAME FOR THE DOOR IN ITS CLOSED POSITION ONA COKING CHAMBER, AND WITH THE OTHER LIMB OF THE Z-SHAPE EXTENDING FROMTHE WEB OF THE FRAME OUTWARDLY OF THE DOOR AND FREELY SLIDABLE INTO ANDOUT OF THE CIRCUMFERENTIAL RECESS ALONGSIDE THE INNER WALL THROUGH ITSOPEN ENTRANCE PASSAGE FROM THE INNER SIDE OF THE DOOR; PRESSURE STUDSCREWS ACCESSIBLE FOR MANIPULATION FROM THE EXTERIOR OF THE FRAME RECESSAND EXTENDING LATERALLY THROUGH THE OUTER SIDE WALL OF THE FRAME RECESSAND INTO THE RECESS SPACE BETWEEN THE INNER AND OUTER WALL THEREOF INPRESSURE ABUTTING IMPERFORATED RELATION WITH THE LIMB OF THE FRAMEALONGSIDE THE INNER WALL IN THE FRAME RECESS, FOR IMPERFORATELY CLAMPINGSAID LIMB GAS TIGHT AGAINST SAID INNER WALL; SAID INNER SIDE WALL BEINGSPACED A DISTANCE CLOSER TO THE AXIS OF THE DOOR BODY IN THE REGIONBETWEEN THE STUD SCREWS AND THE WEB OF THE Z-SHAPED FRAME THROUGHOUT THELONGITUDINAL AND HORIZONTAL PARTS OF THE RECESS, THAN INTHE REGIONBETWEEN THE SAID SCREWS AND THE OUTER FREE EDGE OF THE LIMB IN THERECESS, FOR CAULKING THE SPACE BETWEEN SAID INNER WALL OF THE RECESS ANDTHE LIMB OF THE Z-SHAPE FRAME THEREIN, FROM THE INNER SIDE OF THE DOOR,WITH PACKING THAT IS THICKER THROUGHOUT THE LONGITUDINAL AND HORIZONTALPARTS OF THE LIMB IN THE RECESS, IN THE REGION BETWEEN THE STUD SCREWSAND THE WEB OF THE Z-SHAPE FRAME, THAN IN THE REGION ALONGSIDE THE INNERWALL OF HE RECESS BETWEEN THE STUD SCREWS AND THE OUTER FREE EDGE OF THELIMB IN THE RECESS; AND ADJUSTABLE PRESSURE MEANS MOUNTED ALONGSIDE, ANDACCESSIBLE FROM THE EXTERIOR OF , THE OUTER SIDE WALL OF THECIRCUMFERENTIAL RECTANGULAR FRAME RECESS, FOR EXERTING SEALING PRESSUREON THE INWARDLY EXTENDING LIMB TO ITS TERMINAL FREE SEALING EDGE AGAINSTA SEALING SURFACE ON A DOOR FRAME IN CLOSED POSITION OF THE DOOR, SAIDADJUSTABLE PRESSURE MEANS EACH COMPRISING A PISTON ACTING ON THE LIMB,AN ADJUSTABLE SCREW, A PRESSURE TRANSMITTING SPRING INTERPOSED BETWEENTHE PISTON AND THE ADJUSTABLE SCREW, A BORE IN THE ADJUSTABLE SCREW, ANDA STEM ON THE PISTON EXTENDING THROUGH THE BORE AND TERMINATING IN ANOUTWARDLY VISIBLE FLUSH RELATION WITH AN OUTWARDLY VISIBLE SURFACE OFTHE ADJUSTABLE SCEW, WHEN THE DOOR IS CLOSED WITH THE SPRING AT NORMALSEALING PRESSURE.